Apparatus and method to fill flashlamps

ABSTRACT

To make flashlamps in which the filler material has sharply bent foil shreds, which are buckled, the shreds are sucked through a supply tube by an air flow, preferably of about 3 at and accelerated in the first conduit, which terminates in a chamber, or end wall against which the threads are flung so that they will buckle by the impact; the buckled foil shreds are then removed by an air flow of, for example from 2 to 3 at, in a direction essentially perpendicular to the original direction of flow, the second conduit terminating in a second chamber having another end wall against which the already buckled shreds are flung to be again buckled to form final sharp bends. The sharply bent shreds are then moved by means of residual air flow into a lamp bulb, and then sealed into the bulb.

United States Patent 1 Kaufmann et a1.

[ APPARATUS AND METHOD TO FILL FLASHLAMPS Inventors: Peter Kaufmann, Stadtbergen;

Reinhold Liepert, Wortelstetten, both of Germany [73] Patent-Treuhand-Gesellschaft fur elektrische Gluhlampen mbl-l, Munich, Germany Filed: Oct. 13, 1971 Appl. No.: 189,037

Related US. Application Data Division of Ser. No. 18,875, March 12, 1970, Pat. No. 3,630,650.

Assignee:

[30] Foreign Application Priority Data Mar. 17, 1969 Germany i. P 19 13 417.9

[5 6] References Cited UNITED STATES PATENTS 2/1964 Anderson et a1. 29/25.ll

AIRFLOW approx. 2-3 atm.

AIRFLOW approx. 3atm June 19, 1973 2,772,703 12/1956 Bennett et a1. 141/1 Primary ExaminerCharles W. Lzanham Assistant Examiner.l. W. Davie Attorney-Flynn & Frishauf [57] ABSTRACT To make flashlamps in which the filler material has sharply bent foil shreds, which are: buckled, the shreds are sucked through a supply tube by an air flow, preferably of about 3 at and accelerated. in the first conduit, which terminates in a chamber, or end wall against which the threads are flung so that they will buckle by the impact; the buckled foil shreds are then removed by an air flow of, for example from 2 to 3 at, in a direction essentially perpendicular to the original direction of flow, the second conduit terminating in a second chamher having another end wall against which the already buckled shreds are flung to be again buckled to form final sharp bends. The sharply bent shreds are then moved by means of residual air flow into a lamp bulb, and then sealed into the bulb.

7 Claims, 7 Drawing lFigures FIG.3

PATENIEB JUN] 9191a MET 1 or 3 FIG. 2

PATENTED N 9 SPEEI30F3 FIG.5

AIRFLOW p ox. Batrn APPARATUS AND METHOD TO FILL F LASHLAMPS This is a division of application Ser. 18,875, filed Mar. 12, 1970 now U.S. Pat. No. 3,630,650.

This invention relates to apparatus to fill flashlamps, and to a method of filling, and more particularly to fill flashlamps for photographic uses having a bulb of small volume, preferably below 1 cc, which contains combustible material of filamentary, twisted or crumpled shreds or metal foil therein.

Lamps of this type are required to give off a large quantity of light in a short period of time. The period of time between application of the ignition voltage and attainment of the peak value of light output, the socalled peak time, should be in the range of about 13 msec. in compliance with international conventions. This requirement imposes special restriction with respect to the quantity of the combustion-supporting medium (generally oxygen) and the type of combustible material within the bulb of the lamp.

It is well known to cut narrow shreds of combustible foil off of a broad ribbon of foil by means of a rotary shaft having transversecutting edges. The shreds are then pneumatically sucked into the interior of the bulb through a feed conduit, crumpled by impinging on the bulb wall, and distributed within the bulb by the airflow as described, for example, in U.S. Pat. No. 2,347,046. It is also known to provide a chamber in the suction conduit wherein the foil shreds are caused to impinge repeatedly on the wall of the chamber, thereby crumpling the foil shreds (see U.S. Pat. No. 3,120,694).

In the known flashlamps the combustible material extends within the bulb and on the bulb wall in relatively large, arbitrarily shaped loops. In these flashlamps, the peak time (that is, the time until attainment of the peak light value) is generally considerably below the generally fixed time of 13 msec. This is mainly true for bulbs of small volume and high fill pressure.

The main object of the present invention is to provide apparatus and a method to fill a flashlamp having improved performance and having a longer peak time with a given amount of combustible material.

The apparatus and method of the present invention are particularly adapted to the manufacture of flashlamps comprising a bulb of small volume, preferably below 1 cc, and containing combustible material of filamentary, twisted or crumpled shreds of metal foil which is sharply bent, such as by buckling. Each foil has from 8 to 50 bends and preferably from 12 to 30 sharp bends per 100 mm of length of the foil shreds. The foil shreds have a cross-sectional area of from 2 to X l0 mm The sharply bent shreds thereby form a ball with a cross-sectional area of from 40 to 8 mm, and preferably from 30 to 12 mm per 100 mm of shred length. The sharp bends in the foil shreds have a radius of curvature substantially smaller than 0.3 mm and the formed angle of an individual bend is generally less than 60 in a preferred case.

Apart from the surprising lengthening of the peak time (that is, lengthening of time until attainment of the peak value) in spite of the use of the same quantity of material in the bulb by the repeated sharp bending through a comparatively small angle, the deformation of the foil shreds has the further advantage that with a uniform distribution within the bulb, the bearing area of the combustible material on the inner surface of the bulb wall is small. In the prior art lflashlamps large portions of the loops of combustible material are linearly abutting the bulb wall whereas the contact of the sharply bent foil shreds with the blllib wall is more punctiform. This point contact with the bulb wall apparently promotes optimum combustion without energy losses due to extensive heat transmission to the glass, and ef* fects also an increase in the quantity of light produced.

The fixing of another rated value for the peak time entails varying the number of sharp bends in accordance with the present invention.

SUBJECT MATTER OF THE PRESENT INVENTION Briefly, the apparatus to fill the flashlamp includes a first conduit, through which foil in shreds is sucked; at the end of the conduit is a wall upon which the shreds impinge, to be buckled thereby and to have sharp bends therein. A second conduit extends from the wall, which may be a wall defining a chamber, to conduct the foil shreds at an essentially perpendicular direction to the first conduit, the second conduit terminating in an end wall against which the shreds are again flung, to buckle them again and form the final sharp bends. Residual air flow is used to conduct the buckled, sharply bent foil into the bulb.

Preferably, the air flow is under a pressure of about 2 to 3 at.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional view of a flashlamp having sharply bent foil;

FIG. 2 is an enlarged sectional view of a portion of a prior art flashlamp with a conventional foil filling;

FIG. 3 is an enlarged sectonal view of a portion of a flashlamp with a sharply bent foil filling;

FIG. 4a-c show various illustrations of the ball formation as a function of the number of sharp bends for a foil shred; and

FIG. 5 illustrates a device according to the present invention for fabricating the sharply bent foil shreds when producing a lamp.

The lamp illustrated in FIG. 1 compriss a tubular bulb 1 having an outer diameter of 6.3 mm, an internal length of 15 mm, and a volume of 0.2 cc, the bulb 1 being coated with a varnish coat 2 as a protection from shattering. The filling 3 comprises l4 mgrs of zirconium in the form of foil shreds 4 having a length of mm, a width of 32 u, and a thickness of 20 a. Each individual foil shred 4 has about 27 sharp bends therein, the radius of curvature of each individual bend being smaller than 0.3 mm, and the formed angle for each bend beingless than 60. Each of the bent shreds 4 forms substantially a ball, each ball having a crosssectional area of approximately 15 mm The lamp is filled with oxygen at a pressure of 18 atm. The flashlamp uses conventional ignition means 5, and conventional leads 6 and 7 coupled to the ignition means 5.

FIG. 2 shows in the prior art flashlamps, the relatively large loops of shredded foil filling 4 which often lin early abut the bulb wall 1. FIG. 3,. on the other hand, shows the sharply bent structure of foil shreds 4 and their substantially punctiform contact with the bulb wall 1.

FIGS. 4a-c illustrate respectively individual foil shreds (FIG. 4a) in the hitherto conventional form, shreds with 13 bends (FIG. 4b) and shreds with 28 bends (FIG. 40). The conventionally bent foil shreds of FIG. 4a are distributed in loops over a large area. FIGS. 4b and 40 on the other hand, show the reduced crosssections formed by means of increasing the number of bends in the shreds which form the balls.

FIG. 5 illustrates apparatus in accordance with the present invention for producing the flashlamps with sharply bent foils. As shown in FIG. 5, the foil shreds 4 supplied via tube 8 are sucked in by an airflow of about 3 atm. and are fed to a conduit such as tube 9. The foil shreds 4 are accelerated in tube 9 and flung against the wall of chamber 10. The shreds 4 are buckled by the impact against the wall of chamber 10 and are then flung by an airflow of from 2 to 3 atm. perpendicular to the original direction of flow against the wall of a second chamber 12 via acceleration conduit or tube 11 to thereby form the final sharp bends. With the aid of the residual airflow the sharply bent shreds are passed through the conduit or tube 13 into the lamp bulb 1 which is mounted at the end of tube 13. The lamp bulb is then evacuated and/or filled with the appropriate gases and is sealed off as is well known in the art (see, for example, U.S. Pat. Nos. 2,347,046 and 3,120,694).

We claim:

1. Apparatus for filling a flashlamp bulb with combustible material comprising:

first conduit means for receiving and conducting foil shreds of from 2 to 10 X 10 mm cross sectional area under a predetermined airflow;

a first wall located at the end of the first conduit means substantially perpendicular to the terminal end of the first conduit means upon which said shreds impinge;

second conduit means having an inlet adjacent the wall for conducting foil shreds from said first conduit means and wall in a direction substantially perpendicular to the direction of said first conduit means under a second predetermined airflow, said second predetermined airflow being less than, or equal to said first airflow;

a second wall located at the end of the second conduit means substantially perpendicular to the terminal end of the second conduit means upon which the shreds from said second conduit means impinge said first and second airflows projecting the shreds against said respective walls to crumple the shreds to have from 8 to 50 sharp bends per 100mm length, with radii of curvature less than 0.3mm and bend angles less than 60, and forming an approximate ball-shaped shred mass of from 8-40mm cross sectional area per 100mm shred length; and

third conduit means having an inlet adjacent the second wall for conducting shreds from said second conduit means and second wall to said flashlamp bulb in a direction substantially perpendicular to said second conduit means under residual airflow.

2. Apparatus according to claim 1, wherein said first airflow is approximately 3 atm. and said second airflow is approximately 2-3 atm.

3. Apparatus according to claim 1, wherein at least one of said conduit means terminates in a chamber, the respective wall forming a wall defining said chamber.

4. Apparatus according to claim 1, wherein both said conduit means terminate in a chamber, each, the respective wall located at the end of the respective conduit forming a wall defining the respective chamber.

5. Method of filling a flashlamp bulb with combustible material comprising the steps of sucking in foil shreds of from 2 to 10 X 10 mm cross sectional area through a supply tube by an airflow; feeding the shreds to a first conduit; accelerating the foil shreds in said first conduit; flinging the foil shreds against a first end wall located substantially perpendicular to the terminal end of the first conduit means so that they are flung against the end wall and buckled by the impact against the first stop wall; accelerating the buckled foil shreds by an air flow in a direction substantially perpendicular to theter- .minal direction of movement of the foils;

flinging the shreds against a second end wall located substantially perpendicular to the terminal end of the second conduit means to further buckle the shreds and form final sharp bends therein having from 8 to 50 sharp bends per mm of shred length, a radius of curvature less than 0.3mm and a bend angle less than 60, approximately forming a ball with a cross section area of from 8 to 40mm per 100mm of shred length;

and passing the sharply bent shreds into the flashlamp bulb.

6. Method according to claim 5, wherein the air flow to first buckle the shreds is about 3 at; and the airflow to again buckle the shreds to form the final sharp bends is at a pressure of from 2 to 3 at.

7. Method according to claim 5, wherein the step of sucking in foil shreds comprises sucking in the foil shreds through a supply tube at an airflow of about 3 at, and includes the step of feeding the shreds to a first conduit;

the step of accelerating the foil shreds comprises passing the foil shreds in said first conduit to fling them against the end wall; and the step of accelerating the buckled foil shreds comprises the step of passing the buckled foil shreds in a conduit extending essentially perpen dicular to the original direction of flow of the first conduit, and flinging them against the second end wall. 

1. Apparatus for filling a flashlamp bulb with combustible material comprising: first conduit means for receiving and conducting foil shreds of from 2 to 10 X 10 4 mm2 cross sectional area under a predetermined airflow; a first wall located at the end of the first conduit means substantially perpendicular to the terminal end of the first conduit means upon which said shreds impinge; second conduit means having an inlet adjacent the wall for conducting foil shreds from said first conduit means and wall in a direction substantially perpendicular to the direction of said first conduit means under a second predetermined airflow, said second predetermined airflow being less than, or equal to said first airflow; a second wall located at the end of the second conduit means substantially perpendicular to the terminal end of the second conduit means upon which the shreds from said second conduit means impinge said first and second airflows projecting the shreds against said respective walls to crumple the shreds to have from 8 to 50 sharp bends per 100mm length, with radii of curvature less than 0.3mm and bend angles less than 60*, and forming an approximate ball-shaped shred mass of from 8-40mm2 cross sectional area per 100mm shred length; and third conduit means having an inlet adjacent the second wall for conducting shreds from said second conduit means and second wall to said flashlamp bulb in a direction substantially perpendicular to said second conduit means under residual airflow.
 2. Apparatus according to claim 1, wherein said first airflow is approximately 3 atm. and said second airflow is approximately 2-3 atm.
 3. Apparatus according to claim 1, wherein at least one of said conduit means terminates in a chamber, the respective wall forming a wall defining said chamber.
 4. Apparatus according to claim 1, wherein both said conduit means terminate in a chamber, each, the respective wall located at the end of the respective conduit forming a wall defining the respective chamber.
 5. Method of filling a flashlamp bulb with combustible material comprising the steps of sucking in foil shreds of from 2 to 10 X 10 4 mm2 cross sectional area through a supply tube by an aIrflow; feeding the shreds to a first conduit; accelerating the foil shreds in said first conduit; flinging the foil shreds against a first end wall located substantially perpendicular to the terminal end of the first conduit means so that they are flung against the end wall and buckled by the impact against the first stop wall; accelerating the buckled foil shreds by an air flow in a direction substantially perpendicular to the terminal direction of movement of the foils; flinging the shreds against a second end wall located substantially perpendicular to the terminal end of the second conduit means to further buckle the shreds and form final sharp bends therein having from 8 to 50 sharp bends per 100mm of shred length, a radius of curvature less than 0.3mm and a bend angle less than 60*, approximately forming a ball with a cross section area of from 8 to 40mm2 per 100mm of shred length; and passing the sharply bent shreds into the flashlamp bulb.
 6. Method according to claim 5, wherein the air flow to first buckle the shreds is about 3 at; and the airflow to again buckle the shreds to form the final sharp bends is at a pressure of from 2 to 3 at.
 7. Method according to claim 5, wherein the step of sucking in foil shreds comprises sucking in the foil shreds through a supply tube at an airflow of about 3 at, and includes the step of feeding the shreds to a first conduit; the step of accelerating the foil shreds comprises passing the foil shreds in said first conduit to fling them against the end wall; and the step of accelerating the buckled foil shreds comprises the step of passing the buckled foil shreds in a conduit extending essentially perpendicular to the original direction of flow of the first conduit, and flinging them against the second end wall. 